This invention relates generally to field devices for process measurement and control. Specifically, the invention concerns a magnetic flowmeter with a flangeless process coupling and integrated liner protector.
Field devices include a broad range of process management devices designed to measure and control process parameters such as pressure, temperature and flow rate. These devices have broad utility in a variety of industries, including manufacturing, hydrocarbon processing, hydraulic fracturing and other liquid hydrocarbon extraction techniques, bulk fluid handling, food and beverage preparation, water and air distribution, environmental control, and precision manufacturing applications for glues, resins, thin films, and thermoplastics.
Field devices include transmitters, which are configured to measure or sense process parameters, and controllers, which are configured to modify or control such parameters in order to achieve a target value. Sensor modules also include temperature sensors, pressure transducers, PH sensors, level sensors, and a variety of other devices for characterizing additional process variables and process fluid parameters. More generalized field devices include multi-sensor transmitters such as pressure/temperature transmitters and integrated controllers with both sensor and control functionality. These generalized devices include integrated flow controllers and hydrostatic tank gauge systems, which measure and regulate a number of related process pressures, temperatures, fluid levels and flow rates.
Flowmeters and associated transmitters fill a particularly important role in fluid processing, and they employ a wide variety of different technologies. These include, but are not limited to, turbine flowmeters that characterize flow as a function of mechanical rotation, differential pressure sensors that characterize flow as a function of pressure, mass flowmeters that characterize flow as a function of thermal conductivity, and vortex or Coriolis flowmeters that characterize flow as a function of vibrational effects.
Magnetic flowmeters distinguish from other flow measurement technologies in that they characterize flow via Faraday's Law, which depends upon electromagnetic interactions rather than mechanical or thermodynamic effects. In particular, magnetic flowmeters rely upon the conductivity of the process fluid, such as water containing ions, and the electromotive force induced across the fluid as it flows through a region of magnetic field.
Magnetic flowmeters provide substantial advantages in “dirty” (erosive and corrosive) fluid applications, or under flow conditions in which mechanical and restricted-flow technologies produce an unacceptable pressure drop. Because magnetic flowmeters depend upon electromagnetic induction, however, they also pose a number of engineering design challenges. These include the need for electrically insulating protective liners and specialized flange coupling hardware, which can increase costs and decrease service lifetime. There is thus a continuing need for improved magnetic flowmeter designs. In particular, there is a need for improved process coupling structures that can decrease installation time and maintenance requirements, and more durable liner designs that can increase service life.